Electrical system for aeroplanes and the like



L. M. WOLFFSOHN (NOW JUDlC-IAL CHANGED? NAME L. M. WOOLSON). ELECTRICAL SYSTEM FOR AEROPLANES'AND THE LIKE;

APPLICATIGN mam ma. :3, 1911,

1,362,380. Pa mt fi 19%. "i i, 1920.

. llVVE/VTOR {ML y; B); 5; r

ATTORNEY;

M. WOLFFSOHN (NOW BY JUDICIAL CHANGE OF NAME L. M. WOOLSON).

ELECTRICAL SYSTEM FOR AEROPL'ANES AND THE LIKE.

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noun, 1!. woL'rrsoHN, (NOW BY JUDICIAL CHANGE or NAME LIONEL, M. WOOLSON') or WEEH'A KEN, NEW JERSEY, ASSIGNOR, BY MESNE ASSIGNMENTS, To u k MOTORAPPLIANCEoOMPANY, A CORPORATION or DELAWARE,

ELECTRICAL SYSTEM FOR AEROPLANES AND THE LIKE.

To all whom it may concern:

, Be it known that I, LIoNnn M. VVOLFF- soHN, a citizen of the United States, and a resident of Neehawken, in Hudson county, State of New Jersey, have invented an Improvement in Electrical Systems for Aeroplanes and the like, of whiclrthe following is a specification.

This invention relates to aeroplanes and with respect to its more specific features, to the electrical equipment thereof.

One ofthe objects thereof is to provide a practical aeroplane in which the engines are reliably, and conveniently started and electric current rendered available with a minimum of complication and weight of the parts.

Another object is to provide an electrical system for aeroplanes and the like of reliable action, the apparatus for which shall have a relatively small weight,

Another object is to provide an eliicient and economical method of generating and distributingelectric power particularly in connection with systems employing a plurality of gas engines.

Another object is to provide a simple and reliable'me thod necessitating apparatus of relatively small weight, for operating electrical equipment of vehicles, more particularly. of aeroplanes having a plurality of gas engines.

Other ob'ects will be in part obvious, and

. in part pointed out hereinafter.

. The invention accordingly. consists in the features of construction, combinations of elements, steps of the method and arrangement of. parts which will be exemplified in the construction hereinafter set'forth and.

the scope of the application of which will be indicated in the following claims.

In. the accompanying drawings wherein are shown one or more of various possible embodiments of the several features of this invention, F igurel is a perspective .view of an aeroplane, showing the location of apparatus, circuits not being indicated. Fig. 2 is diagrammatic view showing the electrical equipment used in Fig. 1, and Fig. 3 is a'diagrammatic View similar to Fig. 2 of modified arrangement of electrical equipment.

Similar reference characters refer to similar parts throughout the different views of the drawings.

Specification of Letters Patent. Pate t d D 14 1 20 Application filed March 13, 1917. Serial No. 154.467.

As conducive to an understanding of this invention it may be noted that on aeroplanes where driving power of relatively high value is employed, it is'frequently advisable .to divide this power between two or more engines, instead of concentrating it all in one engine. Power, starters are particularly desirable with aeroplane engines which are frequently of a size where-they are difiicult compartment 101, and they drive propellers 102 and 103 respectively. Mounted onengine 1 in the usual relation are the. generator 2 and the starting motori and to engine 1 the generator 2 and starting motor 4 are attached. A single storage-battery 11 for cooperation with the electrical appliances of the aeroplane in a manner to be described below, is located in an accessible place preferably under the pilots seat. The motor starting switches 10 and 10 are shown in the pilots compartment, and'the remaining electrical control switches to be described below are shown 'ontheswitch board 104., all readily accessible to the pilot.

if a separate battery were located near each of the engines, jand arranged to be controlled from the pilots compartment, not only would such batteries be relatively inaccessible, but the much greater weight of the pair and the greater length and consequently weight" of connecting cables, would decrease the usefulness of the aeroplane.

, Referring nowto Fig. 2 of the drawings, which shows the general arrangement of the electrical equipment in Fig, 1, there-is shown associated with engine l iand adapted to be driven thereby by mechanism not shown, preferably a 6 volt generator 2. :Main 4 connects one terminal of generator 2 with terminal of storage battery 11 through a main switch of well known type, comprising a voltagecoil 16 and a series coil 1'7 so wound and connected-as to attract and close contact member 18 upon the volttion of the main switch 3 need not be describedin greater detail' as the invention does not reside therein. Any desired form of voltage regulating means may be emplayed in connection with the generator, but as this forms no part of my invention it is, neither shown nor described. The usual ammeter 6 is disposed between the main switch and the battery and main 7 connects the .other terminal of the generator 2 with terminal 8 of the battery. Starting motor 4: is preferably grounded and has its other terminal connected by lead 9' throughstarting switch 10 to terminal 8 of storage battery 11. The usual flywheel 21 and the pinion 22 of an automatic drive-are also indicated. By preference the drive is ofthe type including a screw shaft 3O conventionally shown, which automatically causes a movement of the pinion 22 into mesh with the gear 21 upon starting of the electric motor. The disposition of parts just described is substantially duplicated, parts corresponding to those de-v scribed above having the same reference numerals with exponent B instead of A.'

The generator 2 associated with and adapted to be driven by engine 1 is, 'as'shofivizi connected between terminal '5 and groun terminal 12 of storage battery 11. The term grounded as applied to aeroplanes and other forms of vehicles to which my invention may be applicable, designatescom nection to a frame or a metallic structure of the machine. Translating devices, such as lamps l4. and pilot lamp 23 are preferably connected across terminal S and 12 of the storage battery 11 and are controlled from the pilots seat by switches, indicated on switch board 104 in Fig. 1.

In this arrangement it is seen that the,

' usual electrical equipments on two separate starting motors 4; and 4: being of a relatively high voltage and connected across the entire battery, to develop relatively high torque so that they may start relatively heavy engines, and having a common return, and the generators 2 and 2 in this embodiment being shown to generate each but one-half the voltage of the battery and being each connected to charge one-half of the cells thereof whereby both weight and expense are saved as compared with generators of higher voltage.

To cause the propellers 102 and 103 to turn in opposite direction, the motors are preferably disposed as shown to turn inopposite directions, and the same is preferably true of the generators, whereby both astatic and dynamic balance of the parts is efiectively brought about.

The modified form of the invention shown in Fig. 3, which" is particularly adapted for an aeroplane having four engines, differs from that shown in Fig. 1 in the use of generators of the same voltage as the motors, all. machines being connected across terminals 8 and 12 of a battery 110, said terminal 12 and one of the terminals of each of the machines being shown grounded, that is, they are connected to a metallic structure of the machine. The modification is furthermore a development of the form shown in Fig. l in so far as it shows the application of my idea to four power plants associated with but a single storage battery. In this form furthermore, one ignition circuit is shown by way of example deriving its current from the terminals of the storage battery 110. There being no invention in the ignition circuit per se, it is shown of conventional form, primary coil 15 being connected across the battery terminals and interrupter 16 being operated by cam 17, alternately opening and closing the primary circuit. Secondary coil 18 is shown grounded at one end and connected to the distributer 19 at the other, from which the secondary current is led in succession to the spark plugs 20. that shownand similarly operated from the Ignition apparatus similar to battery may be associated with a plurality 'rial, Also, as in the other embodiment described above, a static and dynamic balance is preferably brought about by causing half of the engines, propellers, generators, and motors to turn in one direction and half in the other. In this modification, parts corresponding to those shown in Fig. have the same reference numerals with exponents U, D, E and F respectively for the four power plants.

If a separate battery were located. near each of the ower plantsshown in Fig. 3

and the cables .were led to switches in the pilots compartment, the larger weight of the plurality as opposed to the single battery and the greater length of cable would decrease in particular the usefulness of an aeroplane of which the system might be a part;

If a separate battery be employed for each of the power-plants shown in Fig. 2, not only would the objections described with reference to Fig. 3 be present but the problem able extent.

must be at least large enough to rurnish the .45

be apparent that a single battery employed for the larger electrical equipments shown in Figs. 2 and 3, would have to be of greater capacity, and that the, battery in Fig. 3, would have to be of greater capacity than that in Fig, 2, to secure proper operation.

' After investigation, .1 discovered that thisis not the case, but that, particularly in'aeroplanes a single battery of a capacity no larger than and of a construction closely resembling theusual automobile battery wi ll operate reliably in association with all'the electrical equipment of the relatively coriplex systems shown. in. Figs 2 and 3, such battery being prefer l somewhat wil lighter construction in toinobiles. Such -S1Il is better"- i nave for her discovered will have substantiall" same life as'those of like capacity used in relativel simple automobile systems. By the use oi such slngle battery, further eiiect saving in cost and a lessening of particularly tentative and subject to modification.

The minimum size of the battery necessary to successfully start an engine under conditions of cold weather appears to be one which will furnish the needed current for short interval required to start the engine without permitting its voltage to fall to an undesin In other words, the battery necessary current without excessive voltage loss. Since the time dui which the engine is cranked under electric power before it starts firing is short, the total ampere hours taken out are small even though the current be high. For this reason the ampere hour capac1ty of even the minimum size battery 15 not greately lessened after each start and the same battery is capable oi making a number.

of further successive starts under conditions approximately the same as for the first Thus, when the size of the battery is determined by its ability to once start a single engine successfull its electrical capacity sufiices for successively starting a plurality of such engines.

There appears to be also a second reason,

which contributes to the successful operation of the electrical equipments of two or more power plants in assoclation with, a single apparently relatively small battery; Since unlike vehicles intended to be operated pri marily on land or water, aircraft, such as aeroplanes, cannot remain at rest in heir medium, but must move at a relatively speed, it is clear that at least one, and normally all of the engines, and therefore at least one and normally all of the generators more particularly in the species of 0' will, while the vehicle is in the air, be in oi fective operation to maintain the storage battery in charged condition. Throughout the operation of translating devices suc lamps 14:, ignition apparatus, etc, connected with the battery asvshown in the two r the drawings, it is thus clear thi single battery will receive current from at least one generator, to replenish its output to the translating devices, as distinguished from. the case of an automobile where it is frequently desirable as is well known, supply current from the battery to the lights for hours at a time, while the engine i not running, thereby greatly depleting the battery. aeroplane operation the storage. battery would thus be called upon w out effective connection of charging generators, merely to provide the current necessary to operate starting motors, and desired to also furnish a small amount oi? current for a pilot lamp 23 "to be used when the machine is stored at night. It thus appears that in this case no great number of ampere hours is osed up without replenishing the source of current.

in the system. shown in Fig. 5 it 131? times be undesirable to charge the b with all four generatorson account the. liability to overcharge. 0n the other hand, it would be undesirable to dispense on timely with all but one of the generators, since, vif a single generator were relic and this went of order accirle there would be no means of replen the battery. To effectively provioe 7 this overcharge, T arrange so that p of the machine can render one or more UK the generators inoperative and his L rent supply from the remaining generator, or generators. I

have shown applied to generat'rs 2 1 and 2 by'way of example, two di ercnt methods of carrying out this objects series with the fieldQ of generato I have shown a hand switch 25 which open, will render the generator inope My second method-for rendering r o inoperative is illustrated in associ i generator 2 which has connected-v terminals a hand switch 25 which in closed position short circuits. both 12 ture and field. is to be understoodthat either the short-circuitin ,or the field-ch cuit opening form oi switch may be a two methods just described for rendering tively employed in connection with each of the generators, or'both types may be used conjointly on diflerent generators of the system. The field-circuit opening type of switch is the preferred form, but it is to be understood that there are peculiarly advantageous features to the other embodiment. The switches just described are preferably located on the switch board 104:- with the other control switches.

By way of illustration I have shown the the generators inoperative, applied one to each of the generators in Fig. 2.

Having reference to the figures of the drawings, the ignition switches and throttles, (not shown), being assumed adjusted, the operation is substantially as follows :--For starting, the switches 10 and 10 or 10, 10, 10 and 10 are depresssed successively in any order whereby each starting motor is set in operation by the battery and is preferably automatically placed into 00- operation-with the engine. The engines are thus started successively, the starting apparatus being preferably constructed to automatically go out of operative relation with the engines, after they are started, said automatic meshing and unmeshing being effected preferably by a construction of the type above referred to. The generators which are driven from the engines will now send current to the storage battery while the main switches are closed, and ignition circuits and lights may in turn derive current from thebattery, when their controlling switches; are closed. If there be danger of overcharging the battery in the system shown in Fig. 3, either switch 25 is opened or 25 closed to place the corresponding generator out of action, or both machines may be rendered inoperative.

-of the power plants, sometime Though the systems shown in Figs. 1 and :2 find their special utility in the ap lication-to aeroplanesas fully described a eve, itis to be understood that these systems may be used to good .efiect for other pun poses. 0n some occasions, it may be desirable to operate less than the fu n mber of power plants or to alternaon less than the full equipment. course, only selected would depressed. s that though the invention F eon applied to two engines in. Fig. 2 and to four engines in Fig. 3, that it may messes this invention could be made or executed without departing from the scope thereof, it is intended that all matter contained in' the above description or shown in the ac-* companying drawings shall be interpreted as lllustrative and not in a 'llmltlng sense Havlng described my invention, what I claim as new and desire to secure by Letters Patent is:

y 1. In an electrical system for aeroplanes and the like, in combination, two gas engines, a separate generator associated with each said engine,-and adapted to be driven thereby, a single secondary battery, one of said generators being connected across onehalf the cells of said battery, the other generator across the other half of said battery,

-a separate starting motor for each engine, each adapted to be connected to' both terminals of said battery, a separate. startin switch for each said motor for effecting sai connection, and additional '.translatingj.de-

vices adapted to be connected across said battery. 1

2. In an electrical system for aeroplanes and-the like, in combination, two gas engines, a separate substantially 6 volt generator associated with each said englne, and

adapted to be driven thereby, a single substantially 12 volt'battery, each said generator being connected to charge one-half the cells of said battery, a separate substantially 12 voltstarting motor for, each engine, each adapted to be connecte d to bolt terminals of said battery, a separate starting switch for each said motor for efiecting said connection and a lightingand an ignition circuit adapted to be from said battery. in testimony whereof, I have signed my ac to this specification this 9th day of March, 1917.

mm. M. worrrsonn. 

